Investigators examining the Jan. 7 fire aboard the
Dreamliner in Boston haven’t ruled out that flames erupted
within the lithium-ion battery container, Peter Knudson said
today in response to questions about the issue.

The 787, Boeing’s most sophisticated jet, has been grounded
worldwide since Jan. 16 after the JAL incident and a battery
overheated on a second Dreamliner in Japan. While the battery
aboard the All Nippon Airways Co. (9202) smoked and was charred, it
didn’t erupt in flames.

Boeing’s proposed changes to the battery were approved for
testing by the U.S. Federal Aviation Administration March 12,
the first step toward getting the plane back in the air. The FAA
approved Boeing’s plan even though the safety board hasn’t found
the cause of the JAL incident. Boeing officials said today in
Tokyo they expect the plane to be flying again within weeks.

Michael Sinnett, Boeing’s chief project engineer, said in
the briefing that investigators hadn’t found evidence of flames
within the Boston battery’s container box, an indication it
worked as designed to limit damage from a battery failure.

A witness who tried to fight the Jan. 7 fire said he saw 3-
inch (7.6-centimeter) flames outside the lithium-ion battery,
and the NTSB has found evidence of high temperatures within
battery cells that failed, according to preliminary safety-board
documents released March 7.

Fire, Explosion

Preliminary estimates are that temperatures within the case
exceeded 570 degrees Fahrenheit (299 degrees Celsius), according
to a factual report released by the NTSB March 7. Firefighters
reported the battery exploded as they attempted to extinguish
it, according to the NTSB report.

Sinnett said the reports of fire and explosion weren’t
accurate.

Boeing is redesigning its batteries to ensure a fire isn’t
possible. Among the new features will be a fire-resistant
stainless steel case that will prevent oxygen from reaching the
cells so fire can’t erupt, Sinnett said.